WELLINGTON, New Zealand  Japanese and New Zealand marine scientists are to study two active undersea volcanoes and life forms near their vents using a mini sub, they said Thursday.

The seafloor study is the first in New Zealand waters by a submarine capable of diving to the bottom of the world's deepest oceans, said New Zealand project leader, marine scientist Cornel de Ronde.

The mini sub, Shinkai 6500, can carry three people to the ocean floor for up to eight hours.

The probe will collect geological samples, hot fluids, gases, and organisms from around the vents of the active Brothers and Healy volcanoes about 300 kilometers (190 miles) out into the South Pacific Ocean from New Zealand.

Scientists also plan to take video footage of spectacular seafloor geological formations during their 17-day trip aboard the Japanese maritime research vessel, Yokosuka, which sails from the northern port of Auckland on Monday.

De Ronde said studies have already shown Brothers Volcano has two distinct vent sites, and "the chemistry of the hot fluids emanating from the two vents differs markedly."

The most active New Zealand offshore volcano, Brothers lies in 1,850 meters (6,100 feet) of water, belching a 700-meter (2,300-foot) -thick plume of very hot liquid carrying minerals such as gold from its large crater.

"The advantage of Brothers ... is that we can study two very different vent habitats inside the one volcano," he said.

The expedition will focus mainly on the biological wealth around the vents, he added.

The other dive target was likely to be the nearby Healy Volcano.

Cameras from surface ships have already revealed a startling assortment of life flourishing in the hostile conditions next to the volcanoes' seafloor vents, with many of the organisms likely to be unknown to science.